kern/106703: [PATCH] vn_stat() fails with files > 2Gb on msdosfs (non 386)

[Axel Gonzalez]

The following reply was made to PR kern/106703; it has been noted by GNATS.

From: Axel Gonzalez <loox at e-shell.net>
To: Tom Rhodes <trhodes at freebsd.org>
Cc: Remko Lodder <remko at elvandar.org>,
 freebsd-gnats-submit at freebsd.org
Subject: Re: kern/106703: [PATCH] vn_stat() fails with files > 2Gb on msdosfs (non 386)
Date: Thu, 14 Dec 2006 20:21:16 -0600

 > > 	One thing that crosses my mind is that (in my believing) the maximum
 > > 	size of a file under msdos(fs) was 2gb, which could explain this
 > > 	"problem" you are seeing. If that is still accurate,
 
 msdosfs_vnops.c:#define DOS_FILESIZE_MAX        0xffffffff
 (4294967295) = 2^32 -1
 
 cp works ok, after patching my kernel, the file is correct (md5 match).
 
 
 
 >
 > Hmm, that is an interesting problem, and I'm digging the fix.
 > FAT32 should handle file sizes up to (2^32)-1 bytes (one byte
 > fewer than four gigabytes.  So we should properly handle this
 > for all FAT32 file systems.
 
 I traced the problem down to the getulong() macro (non 386 version).
 
 Problem is not with handling of the file, clusters, dirs. Just that 
 msdosfs_getattr() reports an incorrect (signed) size, and it makes vn_stat() 
 fail.
 
 If it helps, more info:
 
 MAX_OFF:9223372036854775807
 (max size of any file)
 
 size of the file:
 Correct (ufs): 
 3015487488 0xB3BCB000
 
 msdosfs_getattr():
 reported by w/o patch: 
 18446744072430071808 0xFFFFFFFEB3BCB000
 (this is why it returns EOVERFLOW)
 
 reported with patch:
 3015487488 0xB3BCB000